Trump Warns of 'Riots' If He Is Not Nominated; GOP Vows to Block Obama's Supreme Court Pick; North Korea Sentences U.S. Student to 15 Years. Aired 5-6p ET

Aired March 16, 2016 - 17:00 ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

[17:00:07] TAPPER: Senator Orrin Hatch, thank you so much.

That's it for "THE LEAD." Turning you over to Wolf Blitzer in THE SITUATION ROOM. Thanks for watching.

WOLF BLITZER, CNN ANCHOR: Happening now. Dead on arrival: President Obama names a respected federal judge to fill the Supreme Court vacancy. Senate Republicans have praised him in the past, so why are they vowing to block the nominee?

Unstoppable? Donald Trump puts more states in the win column and knocks a key rival out of the race, but another rival scores a home- field victory. Is that more than just a speed bump on the road to the nomination?

Riot warning. Donald Trump says there will be riots at the Republican convention if he even has close to a majority of delegates and is denied the nomination. Is he making a retreat -- threat?

And cruel and un-usual. North Korea sentences an American college student to 15 years of hard labor, accusing him of removing a propaganda sign in his hotel. Can the U.S. win his release despite tensions with Kim Jong-un's regime?

I'm Wolf Blitzer. You're in THE SITUATION ROOM.

Donald Trump is warning of riots if he gets to the GOP convention with the most delegates but is not nominated. Trump says that, even if he falls short of a majority of delegates, there could be trouble if he isn't automatically made the nominee. That's become an issue because the Ohio governor, John Kasich, won all of the state's primary delegates, slowing the Trump steam roller.

Trump still won the lion's share of delegates in yesterday's contests and knocked Marco Rubio out of the race by winning Florida. But his path to the nomination is now a bit more difficult.

Meantime, Ted Cruz says Kasich has no chance of being the nominee and should drop out so Cruz can battle Trump one on one.

And a battle is now officially under way over another nomination. President Obama today announced he's picked federal appeals court judge Merrick Garland to fill the vacancy on the U.S. Supreme Court. But while Garland is widely respected on both sides of the aisle, Senate Republicans say they will refuse to even consider him, insisting the next president should pick the replacement for the late Justice Antonin Scalia.

Our correspondents, analysts and guests, they'll have full coverage of all the day's top stories. Let's begin with Donald Trump.

Acting as if the nomination is now in the bag and warning of big trouble if he's denied the big prize at the GOP convention, CNN's Sunlen Serfaty has the latest on the Republican race.

Sunlen, what are you hearing?

SUNLEN SERFATY, CNN CORRESPONDENT: Wolf, tonight Donald Trump is already looking ahead, looking toward securing the Republican nomination, predicting that there will be a healing process that happens after this very rough primary. But it is certainly not over yet, and some are now preparing for this to go all the way to the convention.

SERFATY (voice-over): With the math and the momentum, Donald Trump is taking big steps to the nomination.

TRUMP: The fact is we have to bring our party together. We have to bring it together.

SERFATY: Today indicating he's ready to bring the nominating process to a close. The GOP front-runner saying he's done with GOP debates and would skip one scheduled for next week, opting for a policy speech to the pro-Israel organization, AIPAC, instead.

TRUMP: I will say this. I think we've had enough debates. We've had 11 or 12 debates. I did really well in the last one.

SERFATY: With no Trump, John Kasich saying he wouldn't show up either, leading FOX News to cancel the debate. That as Kasich fights to complicate Trump's glide path to the nomination.

KASICH: We put one foot in front of the other.

SERFATY: Winning his first state, his home state of Ohio and promising to bring the fight to the convention.

KASICH: We are going to go all the way to Cleveland and secure the Republican nomination.

SERFATY: Trump today with an ominous warning, telling CNN if he's denied the nomination while having the most delegates going in, there could be violence.

TRUMP: If we're, you know, a hundred short and we're at 1,100 and somebody else is at 500 or 400, because we're way ahead of everybody, I don't think you can say that we don't get it automatically. I think it would be -- I think you'd have riots. I think you'd have riots.

SERFATY: After last night, Trump continues to hold the most delegates, but he still has a tough path to getting the 1,237 delegates needed to clinch the nomination outright, making the chances of a contested convention more likely.

After losing his home state of Florida, Marco Rubio using his exit from the race to blast Trump.

SEN. MARCO RUBIO (R-FL), PRESIDENTIAL CANDIDATE: I ask the American people, do not give into the fear. Do not give into the frustration.

[17:05:07] SERFATY: Emboldening Ted Cruz to intensify his argument that it really is a two-man race based on the math.

SEN. TED CRUZ (R-TX), PRESIDENTIAL CANDIDATE: Only two campaigns have a plausible path to the nomination, ours and Donald Trump's. Nobody else has any mathematical possibility whatsoever. Only one campaign has beaten Donald Trump over and over and over again.

SERFATY: Already out campaigning in Pennsylvania today, John Kasich not dissuaded.

GOV. JOHN KASICH (R-OH), PRESIDENTIAL CANDIDATE: Neither of those guys can win a general election, so maybe they're spoiling it for the Republican Party and for the conservative movement.

SERFATY: Turning into a thorn in the side for Ted Cruz.

CRUZ: John Kasich might take just enough votes to give those states to Donald Trump. If he sticks around, John Kasich will become Donald Trump's best friend.

(END VIDEOTAPE)

SERFATY: And the Cruz campaign is highlighting tonight that it is mathematically impossible for John Kasich to win the nomination before the convention, so get ready to hear a lot more of this argument coming from the Cruz campaign, that Donald Trump is the only one that benefits from a splintered field, with John Kasich staying in the race -- Wolf.

BLITZER: A lot more politics ahead. This is beginning to get even more potentially explosive. All right. Thanks very much, Sunlen, for that.

A month after the death of Justice Antonin Scalia, President Obama today announced his nominee to fill the U.S. Supreme Court vacancy. Federal appeals court Judge Merrick Garland is respected on both sides of the political divide, but that political divide itself may be an insurmountable barrier. Senate Republicans say they'll block the president's pick.

Our White House correspondent, Michelle Kosinski, is following the story for us. So Michelle, where is all this headed? MICHELLE KOSINSKI, CNN WHITE HOUSE CORRESPONDENT: Well, you know, the

White House wants Merrick Garland to be the consensus nominee. Somebody with such stellar credentials, somebody so moderate that it would make Republicans look as bad as possible if they, indeed, won't even consider him.

The White House wants pressure coming from the public, as well, to get this done. And if Senate Republicans don't do it and the White House wants maximum political damage just before the elections.

(BEGIN VIDEOTAPE)

KOSINSKI (voice-over): Facing the political reality that his nominee may never even get a meeting with the Republican senator, much less a confirmation hearing, today President Obama defiantly unveiled his choice for the Supreme Court, Merrick Garland, selling him directly to the American people.

BARACK OBAMA, PRESIDENT OF THE UNITED STATES: I've selected a nominee who is widely recognized not only as one of America's sharpest legal minds, but someone who brings to his work a spirit of decency, modesty, integrity.

KOSINSKI: The president extolled the 53-year-old former prosecutor's hardscrabble background. The long-time Justice Department lawyer and federal court of appeals judge in D.C. grew up in Chicago, earned a scholarship to Harvard and graduated with highest honors.

OBAMA: He put himself through Harvard Law School by working as a tutor, by stocking shoes in a shoe store, and in what is always a painful moment for any young man, by selling his comic book collection. It's tough. Been there.

KOSINSKI: Garland surprised the crowd with emotion, his voice breaking several times.

MERRICK GARLAND, SUPREME COURT NOMINEE: This is the greatest honor of my life, other than Lynn agreeing to marry me 28 years ago.

KOSINSKI: Yet even as Garland's nomination was being rolled out in a carefully choreographed Rose Garden ceremony, it was already being declared dead on arrival on the other end of Pennsylvania Avenue.

SEN. ORRIN HATCH (R-UT), JUDICIARY COMMITTEE: I don't think it's unreasonable to ask our colleagues to put this off until after the next president is elected.

KOSINSKI: No one is challenging Garland's qualifications. The White House says he has more federal judicial experience than any Supreme Court nominee ever. As a federal prosecutor, he worked on cases against terrorists, Timothy McVeigh, the Unabomber.

That experience, however, hasn't calmed Republicans, even those who previously confirmed his appointment to the D.C. Circuit. They say it's not about the person but the principle: not putting forward a nominee who would shift the balance of a court just before a presidential election.

SEN. MITCH MCCONNELL (R-KY), MAJORITY LEADER: Give the people a voice in filling this vacancy.

KOSINSKI: Today the president didn't hold back on all he believes is at stake.

OBAMA: It will provoke an endless cycle of more tit for tat. Faith in our justice system will inevitably suffer.

KOSINSKI: And tonight as the political divisions over the nomination harden, the White House made clear it will sell one message to Americans.

JOSH EARNEST, WHITE HOUSE PRESS SECRETARY: Treat judge Garland fairly. That's all we're looking for here, is just a little bit of fairness.

(END VIDEOTAPE)

KOSINSKI: So credentials are one thing. That doesn't mean everybody is thrilled with this pick. Some say he's 63 years old. He's white; he went to Harvard. Not exactly the most diverse choice. Some liberals worry he could be bad for criminal justice reform, because he often sides with the government on those cases.

On the other hand, conservatives worry that he's willing, in some cases, to uphold restrictions on guns -- Wolf.

Let's bring in Manu Raju. So what do we know? What happened on that phone call?

MANU RAJU, CNN CORRESPONDENT: Well, it probably went as we expected. McConnell reiterated his opposition moving forward with the nomination and basically said that "We're not going to actually have a meeting," because he thinks it would create a political circus. Instead, he wanted to have a phone call, look like he's not being totally unreasonable about considering the nomination.

In fact Chuck Grassley, we are, told also -- he's a Senate Judiciary Committee chairman, he also had a phone call with Merrick Garland. The one difference was that Grassley is willing to meet with Merrick Garland.

That's the one issue that there is some division within the Republican conference: whether or not to actually have a meeting. Some Republican senators who are up for re-election are open to having a meeting. We talked to Rob Portman earlier today, and he said, no, that he would be willing to chat with him. BLITZER: So it's one thing to have a meeting, an informal meeting,

have some coffee, talk. It's another thing to have a formal hearing before the Judiciary Committee. Certainly it's another thing altogether to have a roll call vote either in the committee or on the floor. So far the only cracks you see is whether somebody -- they're going to even have a conversation.

RAJU: Yes, that's exactly right. Really there are only two Republican senators who are open to having hearings. That is Mark Kirk of Illinois and Susan Collins of Maine, both moderate senators. But other senators who are up for re-election, including Kelly Ayotte, I spoke to her. I said, "What do you think about a confirmation hearing?"

She said, "That's up to the Judiciary Committee, and I do not want the confirmation process to move forward."

The Republicans are gambling that they will be in a strong political position by taking that firm line. They think they can be the firewall against a liberal justice, and it gives them an issue to run on.

Now, the Democrats hope that that will change, particularly when this political pressure campaign intensifies. And look for late June, early July, Wolf, as that -- that marker for Democrats. If they can get the political dynamic to change before the party conventions and the August recess, then maybe they can get Garland on the court. If they don't, then probably not.

BLITZER: It's a huge uphill struggle right now for the White House on this nomination. Manu, thanks very much.

Let's get back to the breaking news right now. On the race to the White House, Donald Trump's key supporters, at least one of them, Scottie Nell Hughes of USA Radio networks, is joining us right now.

Scottie, thanks very much for joining us. Are you among those Trump supporters who believe it's already virtually a done deal, he's going to get the nomination?

SCOTTIE NELL HUGHES, USA RADIO NETWORKS: I am. I mean, if you look at Governor Kasich last night, you can tell that common core is very active in the state of Ohio, because in his speech he said that not only is he going to go to the convention with the most delegates, but he believes definitely enough to where there would not be a version of a brokered convention. And that is truly a pipe dream at this point.

Anything Ted Cruz at this point, he would actually have to win almost 80 percent of all of the delegates that are remaining, which we're finding to be impossible.

And when you do have more than 7.5 million Americans who have voted for Mr. Trump, and these are folks who have been -- truly had to fight for this vote, because they have been abused. They have been slaughtered. They have been made fun of on everything from the nightly news to "Saturday Night Live." These folks are immense loyal, and they are immensely strong in supporting Mr. Trump and making sure that he is the nominee for the Republican president.

BLITZER: You believe he'll actually get to the magic number 1,237 needed to clinch the nomination before the convention in Cleveland in July?

HUGHES: Well, honestly, Wolf, I think we woke up this morning to the idea that if you are not sitting there and you're not pushing the front-runner, then you're pushing the Democratic nominee. Whether it's Mr. Trump, whether it's Ted Cruz or if it's the pipe dream of Kasich right now.

And so yes, I do believe right now as we go forward, if we all start unifying, which we need to. After you listen to Hillary Clinton and Bernie Sanders' speeches over the last two days, we have got to start fighting, because that machine is very strong on the other side. And these candidates that are sitting there, and they're talking about, you know, we need to sit there and vote for this person over that person, those kind of political games are the reason why the Republicans have lost in the past, Wolf.

BLITZER: You heard John Kasich, the Ohio governor, say it's now a three-person race. Who does Mr. Trump believe is his main competition right now, Kasich or Cruz?

HUGHES: I actually think his main competition right now is Hillary Clinton, to be honest with you. I think he's already starting as you're seeing by the ad that he released today, he is already sitting there.

I think right now he's going, you know what? I've already pretty much got the general; I've got the nomination. If we go to that point, it doesn't matter the damage that these two do to me, I have to start worrying about bringing in and unifying the entire American people, not just my own party. And that's what we're seeing.

When you're looking at voter numbers like yesterday in Florida, with 3 percent down on the Democrats yet 25 percent up on the Republicans, there is something that is literally fueling this fire and motivating people to cross over or people that are independent to go into the GOP column.

[17:15:13] His goal right now, I think Mr. Trump's goal until we get to November is to continue that momentum and build upon that fire, because I hate to say this, when you're talking about people like Kasich and the divisive language they're using and some of these establishment folks, he might never be able to win those over. So he's got to start bringing in some from the outside.

BLITZER: But you have to admit, Scottie, very often Donald Trump's language is hardly unifying, right?

HUGHES: Well, it depends on who you're talking to. I mean, it's one thing, when you listen to Hillary Clinton's speech last night, she sat there and said, "We need to bring in this group and this demographic and this sector." And yet the one group that she has continued to alienate are the conservatives, are those that come from the right base that are center right.

And so those folks are the ones that have been squelched for the last eight to ten years. Those are the 7.5 million people and that are continuing to grow whose voice has not been able to be heard. Those are who we need to unify.

And I do believe that we can unify without compromising character or principles, which is what has put Mr. Trump going forward at this point. The idea is financial security as well as keeping my family safe, those two principles speak across the board on both sides of the aisle.

BLITZER: I want to play a clip. Donald Trump was interviewed by Chris Cuomo on CNN's "NEW DAY" earlier today; and he said if he's close to getting the magic number but is not quite there and they deny him the nomination, he had what a lot of people are seeing as a threat. Listen to this.

(BEGIN VIDEO CLIP)

TRUMP (via phone): If we're, you know, a hundred short and we're at 1,100 and somebody else is at 500 or 400, because we're way ahead of everybody, I don't think you can say that we don't get it automatically. I think it would be -- I think you'd have riots. I think you'd have riots. You know, we have -- I'm representing a tremendous -- many, many millions of people.

(END VIDEO CLIP)

BLITZER: All right. The word "riots," he said it twice. That's pretty serious. A lot of us remember what happened in 1968 at the Democratic convention in Chicago.

HUGHES: Wolf, I'm very proud, my grandfather was one of the organizers of the 1968 Democratic convention. And one of those folks, and I guarantee right now if he was still alive I think he'd be very proud of my involvement with Mr. Trump.

But this, you have to understand the motivation of the riot here. It's not because people aren't getting their voices heard; it's because the people's voice would be ignored in this case. The majority, the plurality, the majority of the population have voted for Mr. Trump. And the obvious moves that will be made by the establishment Republican Party to keep him from this nomination, that right there would cause anger. And that would be an obvious backhand to all of the people who have been paying attention and who have been engaged in this political process.

So you know, riots aren't necessarily a bad thing if it means it's because they're standing there and fighting the fact that our establishment Republican Party has gone corrupt and decided to ignore the voice of the people and ignore the process.

BLITZER: Scottie, you really don't want riots to emerge at the Republican convention in Chicago where people could be injured, people could be hurt, they could be maimed. You don't want riots. HUGHES: It's not riot as in a negative thing what we've seen in the

past. The fact is you have a large amount of people that will be very unhappy. I don't think they would sit there and resort -- in fact, I know they would not resort to violence. I know they would not do it.

However, they would make sure their voices are heard, that they can't be ignored.

When we sit here and talk about -- you have to understand there's a process of these delegates being elected, and that's why I'm very skeptical of this idea that we will not have Mr. Trump as our nominee as he continues to grow in strength. The majority of the delegates going to this convention have pledged their allegiance or have sat there and said that they are a supporter of Mr. Trump. They will be the majority.

So if something happens to ignore their voice as they are representatives of the people, then I think right now there will need to be some way of getting the establishment's attention.

I, however, don't think that will happen. I don't consider riots to be a violent thing unless they turn into -- I consider it to be something where you'll have the majority of the people will be engaged and will be paying attention to what is going on. And it will be an obvious kidnapping of the voice of the people and ignoring of what the people want over what the minority of the establishment wants.

BLITZER: Scottie, we're taking a quick break but remember even last Friday night in Chicago, Donald Trump himself cancelled that rally, because he was afraid there were people going to get hurt as a result of the protests that were going on, the violence that potentially could have occurred.

Stand by. We have more to discuss. Much more right after this.

(COMMERCIAL BREAK)

[17:24:04] BLITZER: We're following the breaking news: Donald Trump threatening there would potentially be riots if he's denied the nomination at the Republican presidential convention in Cleveland in July.

We're back with Donald Trump supporter Scottie Nell Hughes of USA Radio Networks.

I think we just lost Scottie right there. Unfortunately, our connection has dried up. We'll try to reconnect with Scottie. We'll get much more on what's going on. There are other breaking developments on the road -- on the race for the White House right now. Let's take another quick break. We'll be right back.

(COMMERCIAL BREAK)

[17:28:56] BLITZER: We're back with Donald Trump supporter Scottie Nell Hughes of the USA Radio Networks. We've cleaned up that satellite problem we had. Scottie, I just want to make sure that our viewers understand fully

where you're coming from. When you said riots, I think you said riots are not necessarily a bad thing. You didn't really mean that, right?

HUGHES: And let me clarify. Thank you for the clarification, Wolf. I'll be the first to apologize. There are two definitions of riots. On one side it is, yes, it does mean something to disturb the peace a violent way.

But the other definition, technical definition is an impressively large or varied display of something. And I think that's what you're going to have: a large display of emotion if the people that are there that were elected to represent Mr. Trump is not allowed to do the job they were elected to do and vote for Mr. Trump, who has gotten the majority of the population, the majority of the delegates. That's what you're going to see.

In no way would Mr. Trump nor myself ever want to see probably -- would ever want to see anything violent or any harm come to anybody. Hence why he took such a big precaution on Friday night to cancel that so that no one could be hurt.

And so to sit there -- before all the hate comes, because I know it's probably already out there, realize it's talking about an overwhelming emotion will be showed, and it will be showed in a way because the American people, their actual -- their actions will be completely ignored if it goes this way of trying to encourage this brokered convention and a name is nominated off the floor, especially if it's one that no one has ever heard was running for president in the first place.

[17:30:22] BLITZER: In the past couple of days Donald Trump has spoken with the Senate majority leader, McConnell, with the House speaker, Ryan. The two have told him to condemn the violence that is seen at some of his events.

He clearly wants to be president of the United States. How does he calm things down right now? Potentially, there could be a lot of trouble in upcoming events.

HUGHES: I think the question is, is you have to actually ask who's the one sparking the trouble? Is it Mr. Trump or is it the people around him that are running against him or going to potentially be his opponents, which are on the other side of the aisle? I think that's the question.

Because the words of Mr. Trump are really very pro-American. And like he says, when you go to his rallies, you do feel like you're a part of a big family. You do feel like -- that people want to see America be great again. It is a very positive, optimistic tone. When you sit there, he gives you the tools to be able to do that. Hence why his message is resonating so well with the majority of people right now.

BLITZER: All right, Scottie, thanks very much for joining us. Scottie Hughes, a Donald Trump supporter. Let's get some more analysis on what's going on. Joining us now here

So let's talk about politics first, Mark. Donald Trump had a very big night last night. We're waiting for Missouri. We still haven't received Missouri yet, right?

MARK PRESTON, CNN POLITICS EXECUTIVE EDITOR: Right.

BLITZER: Still very close, too close to call right now. But he won almost everything else except Ohio. Does he have this virtually locked up right now?

PRESTON: In many ways if you have money and you're forced to make a bet, then you want to put your money on Donald Trump.

However, John Kasich's win last night in Ohio was very significant in the fact that Donald Trump wasn't able to get a big cache of delegates. Now, the question is, moving forward, can John Kasich and can Ted Cruz nibble enough away at the edges to prevent Donald Trump from steamrolling and getting to the requisite 1,230-some delegates remains to be seen. But Donald Trump clearly had a great night last night, as he's had great nights over the past few weeks.

BLITZER: Do you think this is going to go to a contested convention, Jeffrey Toobin?

JEFFREY TOOBIN, CNN SENIOR LEGAL ANALYST: Well, if I could just question a little bit of the premise of your question, you know, we don't even know what the rules of the convention will be. There are a lot of moving parts in a convention. It's been a generation since the -- there was an actual contested convention. It's been longer than a generation since there were multiple ballots in a convention.

So what an open convention means and how the delegates will actually be selected and will they be bound to vote for the candidates who ran in the primaries, that's settled in some states; it's not settled in others. So until we know what the rules of the convention are, we're not even going to know whether Donald Trump actually has it sealed before -- before the convention itself starts.

BLITZER: I spent a big chunk of the day going through some of those rules. Very, very convoluted rules going into a convention; 1,237, that's the number you need pledged delegates to go ahead and get the nomination, but how those delegates -- how much flexibility they have, that's an open question. You make a good point.

Peter, let me play that clip again, because it's generating a lot of commotion out there, the clip that Donald Trump told our Chris Cuomo this morning about what happens if he comes to the convention, he's close but not yet there. Listen to this.

(BEGIN VIDEO CLIP) TRUMP (via phone): If we're, you know, a hundred short and we're at 1,100 and somebody else is at 500 or 400, because we're way ahead of everybody, I don't think you can say that we don't get it automatically. I think it would be -- I think you'd have riots. I think you'd have riots. You know, we have -- I'm representing a tremendous -- many, many millions of people.

(END VIDEO CLIP)

BLITZER: What was your reaction to that? You heard our conversation with Scottie Hughes, a Trump supporter, a few moments ago.

PETER BEINART, CNN POLITICAL COMMENTATOR: Look, given the fact that Donald Trump has incited violence at his rallies, talked about how it was great when people were brought back -- brought out of rallies on stretchers, talked about wanting to punch people, the mention of riots is genuinely disturbing. But I'm of the view that, I think, that a brokered convention is not that likely.

I think if you -- if Donald Trump, if he wins 50 percent of the vote from here going forward, I think it's eminently doable, given the way the states are organized. A lot of them are winner-take-all by delegate. You get a special advantage if you win the state overall. I think he will come close to that number.

And then there will be a couple hundred uncommitted delegates. And I think Donald Trump will have enough leverage to be able to basically lure enough of those people to his side. He'll have a lot to offer them. He's already shown that he was able to lure Ben Carson and Chris Christie over to his side. He's a powerful guy, and he will be on the verge of being the nominee.

[17:35:12] So my guess would be at this point, although lots could change, that we will not get to a second ballot, that he'll be able to get the number he needs to get over that 1,237 on the first ballot.

BLITZER: Rebecca, is there a credible road for Ted Cruz to get enough votes on that first ballot to be the Republican nominee?

REBECCA BERG, REAL CLEAR POLITICS: It's very, very narrow, Wolf. You would have to have a major sea change. You would have to have Donald Trump maybe drop out of the race for some reason. Mathematically, it is possible. It is not for John Kasich, but it's very, very unlikely.

So at this point Ted Cruz already has people on his team working on the idea of a contested convention, looking at how they could scoop up delegates in all of these states.

Oftentimes, you can go in and talk to some of these delegates, and they're bound to a certain candidate, but they're not actually personally committed to that candidate. They're what you would consider double agents. On the second ballot they could possibly support someone else. Ted Cruz has a six-person team already working on trying to bring some of those delegates over to his side in case there is a second ballot.

BLITZER: You wanted to add something, Mark.

PRESTON: You know, when we talk about the rioting in Cleveland and the potential rioting...

BLITZER: Let's hope there's not any rioting.

PRESTON: Absolutely let's hope. But let's look at the situation: it's very combustible right now. You have Donald Trump out there who is saying very inflammatory things. You have supporters who are very committed to him. And then you have this whole other side of this liberal left that is willing to clash with them. So regardless, if Donald Trump, he gets it or doesn't get it, I still think that there's going to be problems in Cleveland.

BLITZER: They're gearing up for those kinds of problems.

Hold your thoughts, guys. I want to take a quick break. There's much more going on, including the news today that the next Republican presidential debate has now been scrapped. We'll explain what happened. Much more right after this.

(COMMERCIAL BREAK)

BLITZER: We're back with our legal and political experts as we cover today's political breaking news, the fallout from Donald Trump's big primary wins.

Marco Rubio, Mark, he's now out, suspended his campaign last night. Where do his delegates go, his supporters, his money?

PRESTON: Well, you would expect that they would probably go to John Kasich at this point. Some of them might go to Ted Cruz. You know, of course, they're bound through the whole -- through the first balloting. As Jeffrey said, it's a very complicated matter.

But the bottom line is Marco Rubio really didn't have as much support as we thought he was going to have. You know, I mean, listen, when we were looking at this Florida debate that CNN did five days before the primary, we thought it was going to be the clash between Jeb Bush and Marco Rubio, and it turned out to be, really, the coronation in some ways of Donald Trump.

BLITZER: You know, it's interesting, there was supposed to be a Republican presidential debate this coming Monday night in Salt Lake City. FOX News was going to host that debate. Donald Trump said he's not going. He's going to speak at the American-Israel Public Affairs Committee instead Monday night.

Kasich said, "If Trump's not going to be there, I'm not going to be there." What's going to be the political fallout from FOX now having to cancel this debate?

BERG: Well, it's very tough for John Kasich and Ted Cruz, because each of them really needs a boost in this race at this point to catch up to Donald Trump, potentially. And Donald Trump certainly doesn't need any extra media attention. He gets plenty without a debate. So this really hurts the other two candidates in this race. And they're going to have to find a way before some of these upcoming primaries to get through -- break through the noise and make a splash. It's going to be much more difficult without the big audience that you get in a debate.

BLITZER: Peter, I want to play for you and for our viewers a new Trump Instagram video going after Hillary Clinton. Watch this.

(BEGIN VIDEO CLIP)

GRAPHIC: When it comes to facing our toughest opponents, the Democrats have the perfect answer...

HILLARY CLINTON (D), PRESIDENTIAL CANDIDATE: Bark, bark, bark, bark!

(VIDEO OF VLADIMIR PUTIN LAUGHING)

GRAPHIC: We don't need to be a punchline! Trump: Make America great again!

(END VIDEO CLIP)

BLITZER: I guess that's a taste of what's to come if it turns out to be Trump versus Hillary Clinton in the general election, right?

BEINART: Yes, to me this is just an illustration of why Donald Trump is such an appallingly bad general election candidate, no matter what some Republicans may want to tell themselves.

This -- that kind of ad may probably appeal to Trump's hard-core supporters, but among women voters, I think it's going to -- a lot of women voters, it's going to go over very, very poorly.

And Donald Trump, we're going to see, if Donald Trump is the nominee, a gender gap that's going to dwarf anything we've seen in a national election before, which is going to mean that Trump is going to have to win such an astronomically high percentage of white male voters that I think it will simply be impossible.

I mean, it's an insulting. Among other things it's crude, and it's insulting, that ad.

BLITZER: Next time you'll tell us how you really feel about that ad, Peter.

Jeffrey, while we have you, let me get Jeffrey Toobin. He's a Supreme Court expert. We do know the president today nominated Merrick Garland to be the next United States Supreme Court justice. He's got an uphill struggle right now. It doesn't even look like the Republicans are going to hold hearings, let alone have a vote. So what was the president thinking? What is he trying to accomplish?

TOOBIN: Well, I think he's trying to accomplish getting Merrick Garland on the Supreme Court. He is -- you know, he believes that the process can work. Merrick Garland, I think anyone would acknowledge, is imminently qualified to be on the Supreme Court. He's certainly one of the most distinguished appellate judges in the country.

But this is a political struggle. And the Republicans recognize that, in a 4-4 court, four liberal -- four Democratic appointees, four conservative appointees at the moment, this seat is so critical to them that they are willing to take some political heat to draw an absolute bar to Barack Obama filling it.

[17:45:09] Now it may be that they wind up getting a more liberal appointee from a President Hillary Clinton next January, but that's a risk they're willing to take.

North Korea sentencing an American college student to 15 years of hard labor for allegedly removing a propaganda sign. Can the U.S. gain his release? Stand by.

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[17:50:06] BLITZER: North Korea sentenced an American college student to 15 years of hard labor accusing him of taking down a propaganda sign in his hotel. Efforts are now under way to try to get his release but the incident comes amid growing tensions with Kim Jong- Un's regime.

CNN's Brian Todd is here on THE SITUATION ROOM. What are you learning about this very disturbing development?

BRIAN TODD, CNN CORRESPONDENT: Wolf, absolutely disturbing. Wolf, tonight, U.S. officials are calling this sentence a piece of political gamesmanship by the North Koreans. They are calling for Kim Jong-Un's regime to pardon this young man, Otto Frederick Warmbier. And we have learned bizarre new details tonight of the dramatic court proceedings that led to his sentence.

(BEGIN VIDEOTAPE)

TODD (voice-over): In a trial reported to have lasted only one hour, North Korean officials present fingerprints, photos of a political banner allegedly stolen. Surveillance images. They claim this is proof that American student Otto Frederick Warmbier committed crimes against the regime. In court Warmbier pleads for mercy.

OTTO FREDERICK WARMBIER, AMERICAN STUDENT HELD IN NORTH KOREA: My brother and my sister need me. I beg that you see how I am only human. How I have made the worst mistake of my life.

TODD: It didn't work. Tonight Warmbier is sentenced to 15 years hard labor. That's according to a North Korean official who spoke with CNN.

(On camera): What are the conditions he'll be facing?

GREG SCARLATOIU, COMMITTEE FOR HUMAN RIGHTS IN NORTH KOREA: He may be forced to work in agriculture as it happened with other American prisoners. He may spend his days planting apple trees, for example.

It will be fairly grueling forced labor. It is very likely that he will be interrogated by agents of the state security department. This is the North Korean Gestapo. The internal security agency, if you will.

TODD (voice-over): Human rights groups say similar conditions were experienced by American missionary Kenneth Bae who was held in North Korea for about two years. Tonight Otto Warmbier's family is not commenting on his sentence.

U.S. officials tell CNN they are working to secure his release and are urging Kim Jong-Un's regime to pardon the young American.

MARK TONER, STATE DEPARTMENT SPOKESMAN: The department believes that the sentence is unduly harsh for the action Mr. Warmbier allegedly took.

TODD: Warmbier was on an organized tour when he was detained by the North Koreans on January 2nd. In a bizarre twist, the regime claimed he was encouraged to steal the banner by his church, by a secretive organization at his school, the University of Virginia, and by the CIA.

A U.S. official tells CNN that's absurd, says it's propaganda. Kenneth Bae and another American, Matthew Todd Miller, had also been accused of perpetuating hostile acts against Kim's regime. They were given long sentences of hard labor but released much earlier.

SCARLATOIU: Based on previous such instances, I would say that Otto Warmbier would stand a fair chance of being released after about six months since his arrest.

(END VIDEOTAPE)

TODD: But analysts say it's very likely that Kim Jong-Un's regime will use Warmbier as leverage and will want a VIP from the U.S. to make a pilgrimage to North Korea to get to him. When Kenneth Bae and Matthew Todd Miller were released, U.S. director of National Intelligence, James Clapper, went to Pyongyang to pick them up. Former Presidents Bill Clinton and Jimmy Carter have made similar missions to North Korea to get Americans released. You can look for the North Koreans to be angling for something like that -- Wolf.

COSTELLO: I'm sure they will do that. Brian, thanks very much.

Let's bring in our global affairs correspondent, Elise Labott.

Elise, what do you know? What is the U.S. doing to try to get this young American student out of there?

ELISE LABOTT, CNN FOREIGN AFFAIRS REPORTER: Well, Wolf, everything is being done both through official government channels and outside. You know, the Swedes that are the U.S. protecting power for the U.S. over there finally were able to see Otto Warmbier last week. We understand -- and now we understand today Governor Bill Richardson, who has a lot of experience in trying to get U.S. Americans in detention released, including in North Korea, today met with North Korean diplomats on the request of his parents and Ohio governor, presidential candidate, John Kasich, who is from his home state.

Governor Richardson told me just minutes ago, Wolf, that he met today with North Korean officials, asked for Otto's release. These North Korean diplomats in New York at the U.N. mission are not really the ones that make decisions, but they said they'd pass it along. And these things kind of go into a pattern. Now that this student has been sentenced, now I think the negotiations will start to begin.

Obviously, as Brian said, North Koreans really are going to be looking for some concessions from the U.S. possibly some kind of visit. You know, but, Wolf, there are a lot of warnings from the State Department about traveling to North Korea today. Again, the State Department warning Americans, do not travel to North Korea.

[17:55:02] BLITZER: Elise, thanks very much. Let's hope they get this young man out of there and out of there soon. Appreciate it very much.

Coming up, Donald Trump is warning of riots if he gets to the Republican convention in Cleveland in July with most of the delegates but fails to gain the nomination. Is he making any threats?

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BLITZER: Happening now, breaking news. The nominee. The stage set for political warfare as President Obama announces his choice to fill the Supreme Court vacancy. Judge Merrick Garland, widely respected by many Republicans, who nonetheless are vowing that no Obama nominee will get a hearing. How will the supreme battle play out?

The frontrunner. Donald Trump calling on Republicans to unite behind him after his latest string of primary victories and predicting riots -- riots if he's blocked at the party convention.